phil882 Posted January 31, 2015 Share Posted January 31, 2015 Could you explain the implications of that for those of us who didn't major in the hard sciences? Thanks. I would think that more tropical moisture being advected in would help pump the ridge east of the storm, and force it further north, as well as helping strengthen the system which would also favor it trying to cut as far as possible. It goes back to what happens when you have a phase change of water. When clouds condense from a gas to a liquid (forming clouds from cloud droplets) it releases heat. When you release heat you warm up that layer of the atmosphere. When you warm up a layer of the atmosphere you increase the thickness of the atmosphere (remembering that air expands as it gets warmer). Thus, the more convection and the more heat release due to water phase changes, the more you cause that atmospheric layer to expand and raise mid to upper level heights downstream of the parent cyclone. Link to comment Share on other sites More sharing options...
Guest Pamela Posted January 31, 2015 Share Posted January 31, 2015 All 3 runs of the NAM (12z, 18z, 0z)...the rain / snow line is within 10 mile n/s parallel...its model noise / negligible differences. Link to comment Share on other sites More sharing options...
NycStormChaser Posted January 31, 2015 Share Posted January 31, 2015 Larry Cosgrove just said he believes NYC will stay mostly snow. He did say that maybe sleet makes into Staten Island. I agree with him. Definitely a washout. Link to comment Share on other sites More sharing options...
rogue Posted January 31, 2015 Share Posted January 31, 2015 Most SWFEs are positively tilted and they cut all the time. SWFEs almost always trend north at the end and warmer at mid levels from the 850mb low track and south. The storm is becoming more amplified because the S/W is strengthening on models and the confluence is too transient and weak to stop it. Let's see what other models have to say, but this isn't a storm I'm comfortable with for all or mostly snow for NYC. SWFE's almost always trend north? I'd like to see the supporting data on that. Respectfully disagree. Obviously, there are a multitude of factors at play. Link to comment Share on other sites More sharing options...
BxEngine Posted January 31, 2015 Share Posted January 31, 2015 I agree with him. Definitely a washout. Huh? Link to comment Share on other sites More sharing options...
jm1220 Posted January 31, 2015 Share Posted January 31, 2015 SWFE's almost always trend north? I'd like to see the supporting data on that. Respectfully disagree. Obviously, there are a multitude of factors at play. In 07-08 and 08-09 you can look up several examples. SWFEs are common traits of Nina winters, which goes to show how meaningless this Nino has been so far. Link to comment Share on other sites More sharing options...
NYCSNOWMAN2020 Posted January 31, 2015 Share Posted January 31, 2015 All 3 runs of the NAM (12z, 18z, 0z)...the rain / snow line is within 10 mile n/s parallel...its model noise / negligible differences.let's see what gfs says .. Link to comment Share on other sites More sharing options...
phil882 Posted January 31, 2015 Share Posted January 31, 2015 Which would mean more rain I assume.... That is a little too simplistic... the end result is that it would likely mean a stronger, more poleward cyclone. However, since there will be a relatively strong anticyclone to the north, the flow into the surface cyclone will favor northerly flow from this very cold feature (that is reinforced by a good snowpack). If you stay north of the surface low, the surface temperatures may actually be colder with a stronger surface low (stronger surface CAA). That's why this more northern track might decrease the chances of snow in NYC, but probably increase the threat of freezing rain and sleet. Link to comment Share on other sites More sharing options...
jm1220 Posted January 31, 2015 Share Posted January 31, 2015 GFS also looking like it's north of 18z. By hr 60, the 0c line at 850 is just about over the LI Sound, and the 850 low is over north central PA. That has to change in a big way and soon. Looks like more of a front-end snow event than the NAM though, maybe a half inch liquid before a changeover for near NYC. Link to comment Share on other sites More sharing options...
wthrmn654 Posted January 31, 2015 Share Posted January 31, 2015 Can it really get to 40 on Wednesday ?! I'm fixing that really hard to believe, then again it was on the weather channel I seen it lol Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 GFS also looking like it's north of 18z. By hr 60, the 0c line at 850 is just about over the LI Sound, and the 850 low is over north central PA. That has to change in a big way and soon. This isn't looking too good for you guys from NYC on south unfortunately. Surface is below freezing throughout the whole storm on the GFS for NYC. 850s warm up but then crash. Looks like snow to Ice/sleet on this run. Link to comment Share on other sites More sharing options...
wthrmn654 Posted January 31, 2015 Share Posted January 31, 2015 If it shows rain I'm in for a flash freeze event! I have about 31 inches of snow on the ground right now..... Link to comment Share on other sites More sharing options...
jm1220 Posted January 31, 2015 Share Posted January 31, 2015 Surface is below freezing throughout the whole storm on the GFS for NYC. 850s warm up but then crash. Looks like snow to Ice/sleet on this run. I noticed the strong front end burst and edited my post. But I think it's increasingly likely there's a good period of sleet for NYC and rain on the immediate south shores, There could be a nasty freezing rain zone in there somewhere too. Link to comment Share on other sites More sharing options...
stlirish Posted January 31, 2015 Share Posted January 31, 2015 Surface is below freezing throughout the whole storm on the GFS for NYC. 850s warm up but then crash. Looks like snow to Ice/sleet on this run. Snow to ice to Snow then? Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 Snowmaps show 4-6 inches of Snow before changeover to Ice for NYC. Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 Snow to ice to Snow then? Sent from my iPhone Surface line stays right under NYC Link to comment Share on other sites More sharing options...
jm1220 Posted January 31, 2015 Share Posted January 31, 2015 If it shows rain I'm in for a flash freeze event! I have about 31 inches of snow on the ground right now..... You're going to have at least two and a half feet of cement on the ground by the end of this. Good luck with that. Maybe 3.5 inches of liquid in all of it. Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 I noticed the strong front end burst and edited my post. But I think it's increasingly likely there's a good period of sleet for NYC and rain on the immediate south shores, There could be a nasty freezing rain zone in there somewhere too. Agree if the models are right with the 850s temps. Even so, it would just take a tick south for this to be all snow. Link to comment Share on other sites More sharing options...
stlirish Posted January 31, 2015 Share Posted January 31, 2015 Hmm. Will be interesting to see the surface temp spread. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
jm1220 Posted January 31, 2015 Share Posted January 31, 2015 Agree if the models are right with the 850s temps. Even so, it would just take a tick south for this to be all snow. The trend today is clearly north. We'll see what the other models have to say but I don't think it's likely for this to trend back. The S/W is clearly getting stronger and forcing everything north. Link to comment Share on other sites More sharing options...
RUMG11 Posted January 31, 2015 Share Posted January 31, 2015 Through Monday Link to comment Share on other sites More sharing options...
Guest Pamela Posted January 31, 2015 Share Posted January 31, 2015 In 07-08 and 08-09 you can look up several examples. SWFEs are common traits of Nina winters, which goes to show how meaningless this Nino has been so far. See but here you have a sprawling, concave anticyclone over the eastern half of Canada and a blocking pattern in the Canadien Maritimes with low pressure spinning over Labrador. If you are going to have a north trend...it would usually be associated with a High up over Quebec or New England retreating to the east. Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 Still a good hit before it turns into Ice/sleet for many. Link to comment Share on other sites More sharing options...
stlirish Posted January 31, 2015 Share Posted January 31, 2015 I just wonder how well the models are reading the CAD and the 50/50. One thing is for sure. There is going to be a major squeeze with some very heavy snow on the front end. Thump! If the storm is strong enough and we get the transfer in the right spot we could flip back after some ice. It's just crazy to think how far north this has come over the last 2 days. Models are compete crap this year outside 2 days. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
weatherpruf Posted January 31, 2015 Share Posted January 31, 2015 That is a little too simplistic... the end result is that it would likely mean a stronger, more poleward cyclone. However, since there will be a relatively strong anticyclone to the north, the flow into the surface cyclone will favor northerly flow from this very cold feature (that is reinforced by a good snowpack). If you stay north of the surface low, the surface temperatures may actually be colder with a stronger surface low (stronger surface CAA). That's why this more northern track might decrease the chances of snow in NYC, but probably increase the threat of freezing rain and sleet. That is a little too simplistic... the end result is that it would likely mean a stronger, more poleward cyclone. However, since there will be a relatively strong anticyclone to the north, the flow into the surface cyclone will favor northerly flow from this very cold feature (that is reinforced by a good snowpack). If you stay north of the surface low, the surface temperatures may actually be colder with a stronger surface low (stronger surface CAA). That's why this more northern track might decrease the chances of snow in NYC, but probably increase the threat of freezing rain and sleet. Thank you for that. Now, a little social history. in my 52 years in the NYC metro, I have seen only a handful of serious ice events. We mostly rain, sleet or snow. Typically, we start as snow, go to sleet, then rain. Sometimes, a storm comes in warm and begins as rain. Temps crash and we go to snow. I have read that southern states are more prone to ZR storms. Mods feel free to delete if this is banter. Link to comment Share on other sites More sharing options...
swamplover56 Posted January 31, 2015 Share Posted January 31, 2015 Agree if the models are right with the 850s temps. Even so, it would just take a tick south for this to be all snow. Anthony how are 850's around morristown Link to comment Share on other sites More sharing options...
Nibor Posted January 31, 2015 Share Posted January 31, 2015 Looks like a period of sleet For north east nj on the gfs at hr 60. Link to comment Share on other sites More sharing options...
MJO812 Posted January 31, 2015 Share Posted January 31, 2015 Anthony how are 850's around morristown You are fine Link to comment Share on other sites More sharing options...
NEXtreme Posted January 31, 2015 Share Posted January 31, 2015 I just wonder how well the models are reading the CAD and the 50/50. One thing is for sure. There is going to be a major squeeze with some very heavy snow on the front end. Thump! If the storm is strong enough and we get the transfer in the right spot we could flip back after some ice. It's just crazy to think how far north this has come over the last 2 days. Models are compete crap this year outside 2 days. Sent from my iPhone I'm willing to bet some of these models are under estimating the cold and will tick south RGEM going well further south might be a hint? Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 31, 2015 Share Posted January 31, 2015 The 00Z GFS soundings at LGA are all snow...verbatim...that setup would not verify as all snow in reality though, my guess is 11-13Z would probably go SNPL or PL as the 840-880mb layer us just below 0C and SW winds of 50 kts...generally models will understimate WAA by 1-2C there. Link to comment Share on other sites More sharing options...
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